1. Field of the Invention
This invention relates to a novel trihydroxy unsaturated fatty acid, 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD), which is produced from ricinoleic acid by Pseudomonas aeruginosa strain PR3.
2. Description of the Prior Art
Microbial conversions of unsaturated fatty acids have been widely exploited to produce new, value-added products. Hou, (C. T Hou, "Microbial Oxidation of Unsaturated Fatty Acids", Advances in Applied Microbiology Vol. 41, pp. 1-23, 1995) recently reviewed the work on some biological oxidation systems. Wallen et al., (L. L. Wallen et al., "The Microbiological Production of 10-Hydroxystearic Acid from Oleic acid", Arch. Biochem. Biophys. 99:249-253, 1962) reported the first bioconversion of oleic acid to 10-hydroxystearic acid by a Pseudomonad. The bioconversion of fatty acids to produce mono-, di-, and tri-hydroxy unsaturated fatty acids has also been found (A. C. Lanser et al., "Production of 15-, 16- and 17-Hydroxy-9-Octadecenoic Acid from Oleic Acid with Bacillus pumilus", J. Am. Oil Chem. Soc. 69:363-366, 1992), (C. T. Hou et al., "A Novel Compound, 7,10-Dihydroxy-8(E)-Octadecenoic Acid from Oleic Acid by Bioconversion", J. Am. Oil Chem. Soc. 68:99-101, 1991), (C. T. Hou et al., "Production of a New Compound, 7,10-Dihydroxy-8(E)-Octadecenoic Acid from Oleic Acid by Pseudomonas sp. PR3", J. Indust. Microbial. 7:123-130, 1991) and (C. T. Hou et al., "A Novel Compound, 12,13,17-Trihydroxy-9(Z)-Octadecenoic Acid, from Linoleic Acid by a New Microbial Isolate Clavibacter sp. ALA2", J. Am. Oil Chem. Soc. 73:1359-1362, 1996). The production of a novel compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) from oleic acid by strain PR3 has been described most extensively. Under optimal conditions, the yield of bioconversion is greater than 60%, (C. T. Hou et al., "Production of a New Compound, 7,10-Dihydroxy-8(E)-Octadecenoic Acid from Oleic Acid by Pseudomonas sp. PR3", J. Indust. Microbiol. 7:123-130, 1991). PR3 is a strain of Pseudomonas aeruginosa, and its DOD production is inversely correlated with the accumulation of phenazine 1-carboxylic acid (PCA), (C. T. Hou et al., "Identification of NRRL Strain B-18602 (PR3) as Pseudomonas Aeruginosa and Effect of Phenazine-1-Carboxylic Acid Formation on 7,10-Dihydroxy-8(E)-Octadecenoic Acid Accumulation", World J. Microbiol. Biotechnol. 9:570-573, 1993). The production of DOD and PCA by strain PR3, however, was not consistent, and studies were conducted to stabilize and maximize cultures for the bioconversion of oleic acid.
Oxygenated metabolites of unsaturated fatty acids play a variety of important roles in biological systems. Enzymatic conversion of lipid hydroperoxides to trihydroxy fatty acids has been reported in many higher plants, (B. A. Vick et al., "Oxidative Systems for Modification of Fatty Acids: The Lipoxygenase Pathway", The Biochemistry of Plants: A Comprehensive Treatise Vol. 9, pp.53-90, 1987). 8,9,13-Trihydroxy docosanoic acid is an extracellular lipid component in yeast, (F. H. Stodola et al., "8,9,13-Trihydroxydocosanoic Acid, an Extracellular Lipid Produced by a Yeast", Biochemistry 4:1390-1394, 1965). 9,10,13-Trihydroxy-11(E)- and 9,12,13-trihydroxy-10(E)-octadecenoic acids were detected in beer, (A. Graveland, "Enzymatic Oxidations of Linoleic Acid and Glycerol-1-Monolinoleate in Doughs and Flour-Water Suspensions", J. Am. Oil Chem. Soc. 47:352-361, 1970) and presumably resulted from converting linoleic acid during the barley malting process, (C. Baur et al., "Investigation about the Taste of Di-,Tri- and Tetrahydroxy Fatty Acids", Z. Lebensm. Unters. Forsch. 165:82-84, 1977). Trihydroxy unsaturated fatty acids, 9S,12S,13S-trihydroxy-10-octadecenoic acid and 11,12,13-trihydroxy-9(Z),15(Z)-octadecadienoic acid, isolated from rice plants with blast disease, exhibited antifungal activity, (T. Kato et al., "Structure and Synthesis of Unsaturated Trihydroxy C-18 Fatty Acids in Rice Plant Suffering from Rice Blast Disease", Tetrahedron Lett. 26:2357-2360, 1985), (H. Suemune et al., "Synthesis of Unsaturated Trihydroxy C-18 Fatty Acids Isolated from Rice Plants Suffering from Rice Blast Disease", Chem. Pharm. Bull. 36:3632-3637, 1988), (B. Gosse-Kobo et al., "Total Synthesis of Unsaturated Trihydroxy C-18 Fatty Acids", Tetrahedron Lett. 30:4235-4236, 1989) and (T. Kato et al., "Structure and Synthesis of 11,12,13-Trihydroxy-9(Z), 15(Z)-Octadecadienoic Acids from Rice Plant Suffering Rice Blast Disease", Chem Lett. 27:577-580, 1986). 9,12,13-Trihydroxy-10(E)-octadecenoic acid was also isolated from Colocasia antiguorum inoculated with Ceratocystis fimbriata and was shown to possess anti-black rot fungal activity, (H. Masui et al., "An Antifungal Compound, 9,12,13-Trihydroxy-(E)-10-Octadecenoic Acid, from Colocasia antiguorum Inoculated with Ceratocystis fimbriata", Phytochemistry 28:2613-2615, 1989). Recently, Hou, (C. T. Hou et al., "A Novel Compound, 12,13,17-Trihydroxy-9(Z)-Octadecenoic Acid, from Linoleic Acid by a New Microbial Isolate Clavibacter sp. ALA2", J. Am. Oil Chem. Soc. 73:1359-1362, 1996) reported the first production of a trihydroxy unsaturated fatty acid, 12,13,17-trihydroxy-9(Z)-octadecenoic acid (THOA), by microbial transformation of linoleic acid with Clavibacter sp. ALA2.